The RNase R from Campylobacter jejuni Has Unique Features and Is Involved in the First Steps of Infection

Bacterial pathogens must adapt/respond rapidly to changing environmental conditions. Ribonucleases (RNases) can be crucial factors contributing to the fast adaptation of RNA levels to different environmental demands. It has been demonstrated that the exoribonuclease polynucleotide phosphorylase (PNPase) facilitates survival of Campylobacter jejuni in low temperatures and favors swimming, chick colonization, and cell adhesion/invasion. However, little is known about the mechanism of action of other ribonucleases in this microorganism. Members of the RNB family of enzymes have been shown to be involved in virulence of several pathogens. We have searched C. jejuni genome for homologues and found one candidate that displayed properties more similar to RNase R (Cj-RNR). We show here that Cj-RNR is important for the first steps of infection, the adhesion and invasion of C. jejuni to eukaryotic cells. Moreover, Cj-RNR proved to be active in a wide range of conditions. The results obtained lead us to conclude that Cj-RNR has an important role in the biology of this foodborne pathogen.